Astronomers witness slow death of nearby galaxy

October 29, 2018, Australian National University
CSIRO's powerful Australian SKA Pathfinder (ASKAP) radio telescope. Credit: CSIRO

Astronomers from The Australian National University (ANU) and CSIRO have witnessed, in the finest detail ever, the slow death of a neighbouring dwarf galaxy, which is gradually losing its power to form stars.

The new peer-reviewed study of the Small Magellanic Cloud (SMC), which is a tiny fraction of the size and mass of the Milky Way galaxy, uses images taken with CSIRO's powerful Australian SKA Pathfinder (ASKAP) radio telescope.

Lead researcher Professor Naomi McClure-Griffiths from ANU said the features of the radio images were more than three times finer than previous SMC images, which allowed the team to probe the interactions between the small galaxy and its environment with more accuracy.

"We were able to observe a powerful outflow of from the Small Magellanic Cloud," said Professor McClure-Griffiths from the Research School of Astronomy and Astrophysics at ANU.

"The implication is the galaxy may eventually stop being able to form new stars if it loses all of its gas. Galaxies that stop forming stars gradually fade away into oblivion. It's sort of a slow death for a galaxy if it loses all of its gas."

Professor McClure-Griffiths said the discovery, which is part of a project that investigates the evolution of , provided the first clear observational measurement of the amount of mass lost from a dwarf galaxy.

"The result is also important because it provides a possible source of gas for the enormous Magellanic Stream that encircles the Milky Way," she said.

"Ultimately, the Small Magellanic Cloud is likely to eventually be gobbled up by our Milky Way."

CSIRO co-researcher Dr. David McConnell said ASKAP was unrivalled in the world for this kind of research due to its unique radio receivers that give it a panoramic view of the sky.

"The telescope covered the entire SMC galaxy in a single shot and photographed its hydrogen gas with unprecedented detail," he said.

Hydrogen is the most abundant element in the Universe, and is the main ingredient of stars.

"ASKAP will go on to make state-of-the-art pictures of hydrogen gas in our own Milky Way and the Magellanic Clouds, providing a full understanding of how this dwarf system is merging with our own galaxy and what this teaches us about the evolution of other galaxies," Dr. McConnell said.

Explore further: Astronomers create most detailed radio image of nearby dwarf galaxy

More information: N. M. McClure-Griffiths et al, Cold gas outflows from the Small Magellanic Cloud traced with ASKAP, Nature Astronomy (2018). DOI: 10.1038/s41550-018-0608-8

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4 comments

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granville583762
3.3 / 5 (7) Oct 29, 2018
Darkdust

While it's true galaxies have to provide dust for their stars, as the milky is absorbing this galaxy
The dust only accounts for a couple of percent of all the dust and stars in this galaxy
Someone has not had their Heineken of late!
Where has all the remaining 90 odd percent of Darkdust disappeared to
Surely that's enough to power this galaxy for billions of years
granville583762
3.3 / 5 (7) Oct 29, 2018
Or if you look at it another way
As our galaxy is the same composition, our galaxy being of Darkdust is sucking all the dust out the galaxy
It's just that as it comes in Dust and Darkdust as two distinct entities
These two entities have to be discussed when they are being referred to as whole
Surveillance_Egg_Unit
3.7 / 5 (3) Oct 29, 2018
"We were able to observe a powerful outflow of hydrogen gas from the Small Magellanic Cloud," said Professor McClure-Griffiths from the Research School of Astronomy and Astrophysics at ANU.


"The implication is the galaxy may eventually stop being able to form new stars if it loses all of its gas. Galaxies that stop forming stars gradually fade away into oblivion. It's sort of a slow death for a galaxy if it loses all of its gas."


Yes, but what is causing that powerful outflow of Hydrogen gas? Is it some kind of "wind" that has come from a supernova in the Cloud? A maelstrom? But such a wind would be pushing Hydrogen gas, which would be dispersed in many directions, I would assume.

Galaxies remind me of a maelstrom - but one that is a never-ending whirlpool. I wonder if a spiral galaxy like our Milky Way has the power to cause an outflow of gas from a smaller galaxy through centrifugal force of the outer arms.
RNP
4 / 5 (4) Oct 30, 2018
@Surveillance_Egg_Unit
Yes, but what is causing that powerful outflow of Hydrogen gas? Is it some kind of "wind" that has come from a supernova .....

To quote the abstract of the paper; "Feedback from massive stars plays a critical part in the evolution of the Universe by driving powerful outflows from galaxies that enrich the intergalactic medium and regulate star formation". So, yes, it is caused primarily by the ejecta from all the supernovae occurring in the SMC galaxy.
I wonder if a spiral galaxy like our Milky Way has the power to cause an outflow of gas from a smaller galaxy through centrifugal force of the outer arms.

I can not respond to this as it makes not sense. However, there is a similar outflow from the Milky Way (see https://www.nasa....per-hour ).

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